// 导出页面为PDF格式
import html2Canvas from 'html2canvas'
import JsPDF from 'jspdf'

export function getPdf(title,id){
    html2Canvas(document.querySelector(`#${id}`), {
        allowTaint: true
    }).then(function (canvas) {
            let contentWidth = canvas.width
            let contentHeight = canvas.height
            let pageHeight = contentWidth / 592.28 * 841.89
            let leftHeight = contentHeight
            let position = 0
            let imgWidth = 595.28
            let imgHeight = 592.28 / contentWidth * contentHeight
            let pageData = canvas.toDataURL('image/jpeg', 1.0)
            let PDF = new JsPDF('', 'pt', 'a4')
            if (leftHeight < pageHeight) {
                PDF.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight)
            } else {
                while (leftHeight > 0) {
                    PDF.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
                    leftHeight -= pageHeight
                    position -= 841.89
                    if (leftHeight > 0) {
                        PDF.addPage()
                    }
                }
            }
            PDF.save(title + '.pdf')
        }
    )
}


export function saveImage(divText, imgText) {
    let canvasID = this.$refs[divText];
    let that = this;
    let a = document.createElement('a');
    html2Canvas(canvasID).then(canvas => {
        let dom = document.body.appendChild(canvas);
        dom.style.display = 'none';
        a.style.display = 'none';
        document.body.removeChild(dom);
        let blob = that.dataURLToBlob(dom.toDataURL('image/png'));
        a.setAttribute('href', URL.createObjectURL(blob));
        //这块是保存图片操作  可以设置保存的图片的信息
        a.setAttribute('download', imgText + '.png');
        document.body.appendChild(a);
        a.click();
        URL.revokeObjectURL(blob);
        document.body.removeChild(a);
    });
}
function dataURLToBlob(dataurl) {
    let arr = dataurl.split(',');
    let mime = arr[0].match(/:(.*?);/)[1];
    let bstr = atob(arr[1]);
    let n = bstr.length;
    let u8arr = new Uint8Array(n);
    while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
    }
    return new Blob([u8arr], { type: mime });
}

